SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8444d78ef76ddd464468f487bef3aad88f7b52a2f25a8bcdea8d68d418bb31cd' 
  AND token = 'TU+zhNZkUzRq48abN+16gfeWMqdSUsTlRKYKUn1e3kM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00095

JSON explain

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