SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'e3c8814a732d4553bce5c95b36b4d4b53c3dd660c90ed79f9ad210df008e7165' 
  AND token = 'Lhd/1e71sVZ2/8VFvqd3hK81rjcBCVBGseqLAtnftAQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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