SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd263043b220c25846e22e5ea23cf9e2242a218afeebfbe4190f83df68bf76655' 
  AND token = 'cBVObNwCpvBEEpja6DhST8dT8Ek8intneov2HKLZkcM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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