SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6782787988d18c6cab12bfc518118faa94c6b54b4b6c9665e7696f880086ccd6' 
  AND token = 'Ef7DNxvfnWInh7ozpRAbRDJ+OAlJnPvSbWCOBAd11GE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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