SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90dad4c37cc6c7f240887b59d2bb18925006977781b22e5f26162c43b73ef328' 
  AND token = 'dMGErSPkaFNKemtYeAmzI1f67mbkyjKE9yIWrYEWNrY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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