SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f7c4de6a4af7b4a3f5a872287890aa7d0336f45817e4780a2da90df26b83454' 
  AND token = 'GQAqFBFj1RAZ75VU5Qtg4FtYwuGMl/4cmCiuUB6892E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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