SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8fb4b9bb1bc3a56cd553648a327fa0034c9e7e1f9a6e7158149eb186bf27ca62' 
  AND token = 'y5621oQTo7H2XN5pTlNStLukbUttWQqWVfBauly8BQ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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