SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f638a723d54664ecccdac8c9a49868136fe93fa9bb131a53a01ef2ec45a77d9' 
  AND token = 'mMhlsXv7JHrUtYQi/xsFWRAyWGbknicjwS4u4VBiWnc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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