SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d8cc43c335b36775f2fb635f326844b54891fe5015c0908abd575e8b3d7dac6' 
  AND token = 'Q2cscTJdg9RuiS4a6FcCBfCMLVHgkZZfwhDqLejqUL4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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