SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd52b5f672d1fbfc928f62473cda782213ecb9d4490b577edbcbdce4725c7186' 
  AND token = 'm9fpsthi2gTyKh1bvbbdF1pvfSTlld871KbqMQGjtQc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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