SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e0b5080e9f197403548a33e64705bc0b5fd5162511d8de11510ea9c2246e4977' 
  AND token = 'A/BAjCwYiKDfGqB02bRYmltIS2E3GOqXvgRThHWnmlk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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