SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b121c30679ba12c3946718a8293a41f2f945712e02b2634fc3cd50aeb34e49c' 
  AND token = 'sYlYlJndNO54L6koRBQwqfuL0iPPhn/lhDkdXjuQEeI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}