SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68aefdb05e73525d99d94cf378926f8e3e8cf1df557c0cef7b58f77a52409c21' 
  AND token = 'hFvfSCQYy45J+VXNIsotV6JR/jQvtP3+nCkqMMXn03w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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