SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '917edddffe54ba15206676309c693d2863ebb20df851d9ecd4e1a82b86e281cb' 
  AND token = 'HRKgRUYAkaUKz9bXTBiko3ISrH1n9zyQ5nnomEDbppY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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