SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8e39e839a34a05ddb102caae40a2eaf791fc027ceeb3e87606b422cc58a258c' 
  AND token = 'PgSXA1Lj1ibtWyyPXdqG3/bATmE81J5hT8izQ92jlFs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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