SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f1d6fb8755e6cd187f3082bcb1dfb90f78dfe69e96780c545f2ba1e8b364a341' 
  AND token = 'hy8QG2JWOVCeMRnSWWDBQ/hqNT+Jc2Rvw6pd0k6KulM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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