SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2efdf706208bf68b17125e5fcd440f3fda06570899cd3efe3c5b15e0d2034832' 
  AND token = '/2C5otMhgH9gU7Z+xiZyefrltfNmzzjYiF9FL4wqFoo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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