SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '982590bd5ebc856ec9cb783573b6813a5e13bc79e844acceb1c4dea991a8e38a' 
  AND token = 'zaIX7BlKpdFlGPjwiLpTkYmnAEVj+Iz4hbzB0zVbEeo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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