SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a3657c3748b9d90cbb1085b437ce6cfe4227d5bd0a8a19a78c2d5db49eef2b8' 
  AND token = 'g6srj310QhDze2PoqwaWmGwwWriLmkv0PT/sXEWqcd4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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