SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b5ab0ade05e54d9cb44eccf9f814d6adeda5fd78a862fabf3d61f34ddddf28f' 
  AND token = 'pvpd8hy6bVAP1dgI2K0O84BnrS3hQzwiYJBoVAIwujw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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