SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ec245d2f2bb8938fe5d642122704ec15f3d04976cf0cc40640b6cd8139fe0c6' 
  AND token = 'lkjQDstyKNkH3tSxJevPhlHMrrPEneFhvCIJai9cTtA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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