SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c532621cdbd7d2b71ad146d5ba328255f65f73aef022f9d91b6e4840514f8c4' 
  AND token = 'FvvKun+qVCHK36iAewhGVrj9QDaquawkYrxeOzKSDmI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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