SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3255a1e9228c37ad1e9a4fa1ccbd9f8cb504193d90bfa98aa4a199209e8765c7' 
  AND token = 'fRRjeML0+1EpK9GPOREVg/E6OHHm3CgyAREObpj9sq8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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