SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98320df0a52f2783806ed97c12f3fa6dab3200458823dba65fe40a156240659b' 
  AND token = '0pq7VATUYZJbp4Yzxkjv9RBDvWcX93ixqrwnlwNXajQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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