SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '634e8db286c0f4d90d5d5012ed6e8a0ab2aefffae10e35c154babc2b1a80d40c' 
  AND token = 'kgkDoCmkwjzEV2Qt5TDk8K+nWf6gijnus5PsRQp8EFQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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