SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd97ce84e0ef050591bae85dd3eb7597382d3a74447279d69641bad8bdb9c9503' 
  AND token = 'D5nd+FLQQdy+ftZpedxAPtI2NQVMdcP7sf4hDshDkrw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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