SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '330bd2d688a63d703b3fc5f6172d29182408ef6dd918859a0e5c05a1ae1a3fcf' 
  AND token = '2JCx/zsgjsXzDTfSBu2FulgqXRWVDRhUfhM9R1WNM8Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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