SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd00537d4f529d5e312ced959ac9664508f8c44ff128eb46ab343bcd18058c722' 
  AND token = '23K4Ij1+qapaxFkD6zbAyUfQ1QGzXMEJKS1MVoMwjYo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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