SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cc276bdba6424dd16adca24a1a0a20ed84805510ee9043eb8c8266396a2431fe' 
  AND token = 'rZqzAnxCWlek+E7ciYd7+RiO10MInDFn9cKIPHIXmLs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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