SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '41fe5246d041a20bd1bdd7fd42411a361f4858afd13561a69f0aebb298952f64' 
  AND token = '6TIkkTiAMYRO6v1u9WOI13VDa1wDNawtzBY7MEvJhzk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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