SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b385eb81f9d95010ce2c87274b88cfb11c9b16278494a69c98e5629543aef6a3' 
  AND token = 'jJJCvJxVDvmN18nU/617HVi/ggI5qvSV749YPhoRtDc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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