SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bbfd6ab653303d1ad236af59577c467a29d4567401ec56d75037a367bcb82fee' 
  AND token = 'Tr72LisG09LYG2fdRQegamT5gqrNWv3LOpz6nQsDZSk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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