SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1fffe1f25db678ad757225bd77017106c013bdf15b8e8764fb399b245f59bc42' 
  AND token = 'RhlyCo6vHU58TEfhTdtLFIOEtZBo+rGsEBenE1knwfc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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