Sandbox

SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55b573a8a788deda1df973142e400ea0a09f10c4bddecb8b4c55019285c8bebd' 
  AND token = '0zjpBoIJ/Fq7eBZy+OGIefHfUw38ggyOOgg66UeZztg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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