SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12fc7c33b467e2a2645fd4bf240cacf2e357592361cb9e5f8d0c01bf8ee51293' 
  AND token = 'jOoC2zuS/qQOhl6YvMXk+lnVAhr21i+fc/+5c1HJgsM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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