SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e94289cf975388e41ae910565feba3bb8044aefe450bd540fbd253a1231462d1' 
  AND token = 'VHm9dpdUIvMsO6efN4IobjB05AM2MwAFiSj82aV5JYw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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