SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '675e488a123cbd06216f0fc4d0859a10887a8763b44a63688c46913d600675a0' 
  AND token = 'nbk0I35+OH95xZWEU11q3PL4eT+FpQTH+Ti9aZMZw68=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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