SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da760452dfbe75e99c4d551d6c68d68d0634d16a3dbf3e4f6104b67ca6319f83' 
  AND token = 'yTWcAiVxgDY4uzwR+wxwmAyyN39kK6QoMCCfMV5VLHA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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