SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c117ec9068b4b696f05e562effad6c0e35881b9d33835af2868e2d2fce17f7ab' 
  AND token = 'p7rrm5qNpIxG1buSAYOVQ69khInfcGDsO7YC1kqene0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}