SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ca91534b62be57ada6012906a31639040c30c0a16ffb294f69723127e5c4753b' 
  AND token = 'erTMeQgsUyFbWveCTe9MoauU2GtVXCt1jQQaacc3cwk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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