SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c702e53f10220fcc2ead9efbc43e79c1cc0c6b0759c7ec88251963765a1f44a' 
  AND token = '6+PaDdK818iN2frA+53XcoX2ZYJU4d/f5wu7UFCkzI8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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