SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a3d8bd3ee99b2d178455dca1e3bfd969c38d2741428434a0fdd5e53fff96c6b' 
  AND token = '+DeB3vtnzbXq6Lubb3VClKUlgxbwO39+Apk/5PugAKU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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