SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0799f56c250fa913215bf14e6bc629b730fe41f31052fceb501485b4be0a750e' 
  AND token = '4nYhlgAWm44wWsnM3icStAbHiU1V0Zvo8FvxiSEHQWw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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