SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '637467a34a36835182e82747c311233d0a7d7d88583d7bb656d71d50d02122b9' 
  AND token = 'irrDIAbyz+WHGUrk9/rIb9GmPM/tcb9WoxZSTu3rGuk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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