SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f1ebaee2c30b39041dedece15e2e8d09eefd0ccc714491f8e0a3bc8e372dbf70' 
  AND token = 'OXPRWwV50eCwxkX98GkojHfrgIrvuaEFClvwxH1r61M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00077

JSON explain

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