SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '174344217c6ce1df86fa43d999ebed48986cbbaa8658d6ce596f682e5c9b18e8' 
  AND token = 'MewjxHjUBCqhurhPFH0MRgisZrEnCm0IfmdAq2sJepg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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