SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '44df783f6d028ee462fc5547ad1e49789579a9b51a9c8da2240618d3531eb438' 
  AND token = 'FwHEV1sDr41ZKI9j7RDAU4vnillnErnVzvLS0JQMKiU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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