SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37dee0d273a8f8930d546229f2f1732a783440ef0a2c374122629722395f5417' 
  AND token = 'Jgfw7RT2Vq+BrdTK+94RS86Mpb2ZBtDYzsNwLU+jF1E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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