SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '509246f2399ee33214b18878cb5879126ab4ee0b22948fa09fb91739ee4358d4' 
  AND token = 'JGSC1Ay70fq3zmDm+oMUeW/WnPKhYCjrX3KgXaypKNY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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