SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5e5c19c3baf3f31e108d0c20bbe88ee7a1d47d45452855765dffbc318d2d7ac0' 
  AND token = 'N0+gJxT7+amp8ZZygaPhgUKsTFRkE+qK/nnqiSvroGw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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