SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '44d2c2f5a8a302a99519aeb97a7c07737da24343e217355120e2254a36de424e' 
  AND token = 'JyuhhXalJihGWKXWFoAiLSF1RtbAyMts+S0yywP/hYQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}