SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '215fb2698fb67036ce3619abb906241fd65af6bab806994eb4780ea0a183de3a' 
  AND token = 'E3eTgf7BJz8MwZkJECfUrDTiJadYrWxg+GYvtnBoL9c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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