SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91502303f268415ddd4bb3f24dbf12e6c95c4b8e1c27f71506b2f6649d4919c2' 
  AND token = 'OT/JMxhLfqgv/GN8QUqa67dAhgkRufwqNS8Lls6VH/M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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