SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aff509e7313248d7cd3b9babe7deb3b059b33fc67a593165a4982d23067ea058' 
  AND token = 'L96Zv6xPqOb0CHNdjGWTaC1tZUh1BAlM49AMsRI5jkE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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