SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '495559205f204d52f3b4044ebd971d7f94b69124071db74bf7f6425273e4c701' 
  AND token = '3RtgW6UOmFGVZvE36rWrvlxhnKWP6wUnZJ6CGYF6BUo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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