SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9c7c240805365289ecb10a1dc11e21661dfc4ad807f47841921d3233ed966ac' 
  AND token = 'LfebywcGvGZ7YCXdCG+ciAfr2iQyJVLeBwqKogJdAws=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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