SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e6479fc4dec80257fad4794096d994023dd8aa415b862276a4f2da7d3a59403b' 
  AND token = 'L9Ypsl1gZseNYC4v4wGqhMjSQsWFYF6DWThle2VUfgU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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