SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '892f857c0245ca6ae8d7e8c4582eba08cec701d5074c449e674b89279bcddcbb' 
  AND token = '5RokPMX5vHItZsgNqkfyuMDuPZorEczhVAf9bTowHJM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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