SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '394cf13b207c67ce9d55ee23296d0fb99c4d51a4797bcec945682c5ac31a4cf0' 
  AND token = 'xrKEnsuLIFvjaCN6THFiQYW9smJ4+TPJhrwJ7cWR/D4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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