SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc17073d323f23c1a596e011de22422f77efffc3a0876e3c453425459cff44b8' 
  AND token = 'KzxMGBi+m9pwL+zoILHQngdBbJKbc6sSWgsdixH9GFs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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