SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8c79c2fbfa3a699461936f3057e43faa13b725f334ece66198ac24de0ffd0dd' 
  AND token = 'kT1mo/aG8sdG1D2OywwiYALk2j0P0CzkFZb6Wy4hcWg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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