SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ffebe82064d24ed8790d3a309a716852d9a5bc915c8c75aaccbce9d26b2c0f0' 
  AND token = 'iW6j1nyvMjQmkgMSZpv312BcPuN4nZGOvJbi9yccxdc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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