SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f6e51caf91e125c5cdfbcc38cb7e87666c34160d677a93617f855fb241cae72' 
  AND token = 'rbRxlEyJr0EwoDSB+mrcG+TjWdDbJJp2CPM3ctyeN9A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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