SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36ef7f79a502a926577222ff7c95183a59c151834edd815eb3fbd07b6d6c3157' 
  AND token = '583e1yBS09i86jnKwbe11VJb+lWnQKspVP9QBtWL6hw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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