SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4871798d264ad5b9920f8f2b562b227c7fa6642dc5e197206243d4bdc458bcd' 
  AND token = 'WEIwO61KAU+SNLlq0G+2HLiBQg19ijbY1q5AFhjqxwo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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