SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e058759140a37aaa138c26b14806f39d82e7d4fa721167d203a4dfc2b49b8868' 
  AND token = '8VPB53FzsP3yA0dFFWTjeLCrlZhjfQcMWVZRCFUyLOw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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