SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b333dbf80d78abcc1d841730926b371c5a441e1f8b2e86ca7544cff3d1de3bfa' 
  AND token = 'fispVBMdSpdIprMl1iy3SkQ+IXTlRqU/1/iBzJdKq4Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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