SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96527f0270111996df5879bc9a88417b8bcbe98c11fb3db94727f81808f433f6' 
  AND token = 'ySOHcikQ2/ICjRDs4Ry5fxMagIEfvD+/1Ypied5lhH8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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