SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8d466a7838bea46a2d51fc574ee0e7ad638aa24981e4b364aa180a6cf61230c' 
  AND token = 'bnxoDGguxPMxIl9jFdrhJYIfxsvsWGlp++Dmh93dNl8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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