SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc8968afd5a0728221e510a409487b94d65fd190e4e7e4ffb4ff599d493376d4' 
  AND token = 'S+X/9gGaPqcdphPgmsxHp1eLoNKDigvIF8vWYI/IFYQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00091

JSON explain

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