SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'abe0ded3723667ba52e9745926dca386193fedc51d83962f93d1cc99616909f4' 
  AND token = 'c/x6Foun3lMjCsfxxwgi/APz9unUcpbPNtZRSzmcIsc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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