SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0ffdbc382b85c2370fae02cf7fc048a2a2c3dd888aad601e3bc1bae6e32cf30c' 
  AND token = 'OK7iE21tZdPsufyklP9Hrci5DzP7NKkAbhaZdaHH2QI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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