SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8020372123d7036e98f15ad0c6959da6e9a5e823cf6f21b575193d7b1625d692' 
  AND token = 'KlXXwHiD97jgLxrXOxhkgDMUNTjC0CzVNS//P0iChfo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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