SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ca855afdd0c5851048ff136277ce488214b52fc5276d6f090515dec1abe49ec0' 
  AND token = '/ndo1VCgCv9XYpaWBvdZiEO3ILwF9L5CKzZT9mMBXIw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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