SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '434be173c189d56b65697c93eb2e68fe7c27be6894b555b012d0d2a62ac18893' 
  AND token = 'lpnSh4IfNZGEXdSmzqF+iFw1J/5ZkvgYw01AiiCVIZo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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