SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '919eb3376120165bb2e2702b55dbd8ec3e3eedc3ec520af1288717b4162038da' 
  AND token = 'YaskT7hpF3Srq570gioY09Kc39CKyMJqXBNjU0YZFtM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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