SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa57944926515ae431276c8275090c4aad27df8d9f59372d1df74e44e6a0551f' 
  AND token = 'RdCtZqmsQMLcO/rPG6H4NluzLvxYvbLFvMIk6Y+fgfQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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